Method for manufacturing an improved polycaproamide filament yarn by sealing a package in a bag

ABSTRACT

A method for manufacturing an improved polycaproamide filament yarn by sealing a package thereof in a bag made of a film of a low moisture permeable thermoplastic synthetic polymer and its product. Oozing out of monomers or oligomers on the surface of the yarn due to high relative humidity during long storage can be effectively prevented.

United States Patent Mizutani et al.

[ 1 Feb. 29, 1972 Carnarms ..53/2l FC [54] METHOD FOR MANUFACTURING AN 2,917,878 12/ 1959 IMPROVED POLYCAPROAMIDE $1 8 v 2 X essinger.... 8 76 X gk c ggl g a gA G SEALING A 3,176,374 4/1965 Kinnear ..28/76 X 3,188,779 6/1965 Elden .53/21 FC 72 l t s Mi m n K i m. 3,343,331 9/1967 French ..53/2l FC 1 gz'z i' 'h is Shim 2,318,380 5/1943 Davis ..128/335.5 3,401,043 9/1968 Finley... ..99/l82 [73] Assignee: Toray Industries, Inc., Tokyo, Japan 3,516,218 6/1970 Eisler ..53/25 [22] Filed Jan 30 1969 3,526,186 9/1970 Cornelius..... 53/127 X [21] AppL No: 795,155 FOREIGN PATENTS OR APPLICATIONS 978,686 12/1964 Great Britain ..53/2l FC [52] U.S.Cl. Tl Primary Emminer wayne A. Morse Jr [51 1 Int. Cl. ..B65b 31/00, B65b 63/08, B65b 55/04 Bums Emmanuel {58] FieldofSearch ..53/21,25, 111, 116, 127; [57] ABSTRACT A method for manufacturing an improved polycaproamide [56] References Cited filament yarn by sealing a package thereof in a bag made of a film of a low moisture permeable thermoplastic synthetic UNITED STATES PATENTS polymer and its product. Oozing out of monomers or oligomers on the surface of the yarn due to high relative hu- 5: midity during long storage can be effectively prevented. a er 2,814,382 11/1957 Lassiter ..53/2l FC 1 Claims, 3 Drawing Figures Process Flow (kart F Frau ac! ape/align? 1 (arm 2290a 1 L.. J

DlW/V Y4)? Mid/0W1? i| Pit/646E Var/z J -ak. Pad/gig find/mm fllrdi'arvll Yarn 7am Drawn Draw/r 0/? Yarn P 711v;

Willa 0g go 1 F '5 limes Ava/1d V NEE/m '6! l/ealea fialler METHOD FOR MANUFACTURING AN IMPROVED POLYCAPROAMIDE FILAMENT YARN BY SEALING A PACKAGE IN A BAG The present invention relates to a method for manufacturing an improved polycaproamide filament yarn by sealing a package thereof in a bag made of a low moisture permeable material and its product.

As is well known, generally polycaproamide filament yarns manufactured by the melt-spinning process contain monomers or oligomers in their chemical constructions. Such monomers or oligomers tend to ooze out on the surface of the yarn during long storage after the manufacture and this causes increase in the surface coefficient of friction of the yarn resulting in troubles during the subsequent weaving or knitting process. Furthermore, such oozed out monomers or oligomers drop off from the yarn surface by abrasion during processing and stick onto yarn guides, tensers, reeds, heald wires or knitting needles. Accumulation of such adhesive substances on the aforementioned members creates further increased frictional resistance against the yarn passing therethrough to cause unstable yarn processing.

As the result of the accumulated efforts by the inventors of the present invention for eliminating processingtroubles of the polycaproamide filament yarn due to oozing out of monomers or oligomers contained therein, it was found that the moisture content of the filament yarn plays an important and determining role in the aforementioned oozing out mechanism of the monomers or oligomers. That is to say, the higher the humidity wherein the caproamide filament yarn is placed for long time, the higher is the degree of oozing out of the monomers or oligomers on the surface of the yarn. On the contrary, when the yarn is placed in a low-humidity condition, very little monomers or oligomers ooze out on the surface of the yarn even after a long storage time.

Further advanced research work by the inventors of the present invention has revealed the fact that very little oozing out of the monomers or oligomers on the surface of the caproamide filament yarn can be realized by sealing a package thereof in a bag made of a low moisture permeable material while keeping the percent moisture content of the yarn below 2.5 percent on an average.

A principal object of the present invention is to provide a method for manufacturing an improved polycaproamide filament yarn which is accompanied with less unfavorable oozing out of the monomers or oligomers contained therein on the yarn surface even after relatively a long storage time.

Another object of the present invention is to provide a method for manufacturing a polycaproamide filament yarn which can be processed throughout the textile manufacturing operations in a very stable condition by eliminating frequent processing troubles which were oftentimes encountered in case of the prior arts. 7 A further object of the present invention is to provide a method for manufacturing a polycaproamide filament yarn which can be woven or knitted into fabrics without forming unfavorable defects on the fabrics.

A still other object of the present invention is to provide a method for manufacturing a polycaproamide filament yarn which can be woven or knitted into fabrics at a relatively high processing efficiency.

A still other object of the present invention is to provide a package of a polycaproamide drawn filament yarn sealed with a bag in a completely isolated condition from the atmospheric humidity.

in order to attain the aforementioned objects of the invention, the method of the present invention comprises making themoisture content of a polycaproamide filament yarn lower than 2.5 percent, or more favorably lower than 2.0 percent, during the drawing process, taking up the yarn onto a package while keeping thus lowered moisture content of the yarn and sealing the package of the yarn in a bag made of a low moisture permeable material.

Further features and advantages of the present invention will be apparent from the ensuing description with reference to the accompanying drawing to which, however, the scope of invention is in no way limited.

FIG. 1 is a graph which shows the relation between the amount of oozed-out monomers and oligomers on the surface of the yarn and the moisture content of the yarn.

FIGS. 2 and 3 are flow diagrams which illustrate the process of the present invention. As shown in FIG, 2, undrawn yarn is submitted to drawing, so that the drawn yarn has a moisture content of less than 2.5 percent. This may be accomplished by heating after the drawing operation, as shown by winding on a heated roller. The yarn is then taken up on a package core and then it is immediately sealed in a bag made of material with a low permeability to moisture, so that the sealed product also has a moisture content of less than 2.5 percent by weight.

HO. 3 illustrates two procedures which may be used according to the present invention. Thus, the undrawn yarn may be subjected to heating during or after the drawing step, to produce yarn having a moisture content of less than 2.5 percent, the drawn yarn is then taken up and immediately thereafter sealed in a bag of low moisture permeability. Alternately, the yarn may be drawn, and then subjected to heating during the winding operation, to produce drawn yarn having a moisture content of less than 2.5 percent.

Referring to FIG. 1, the amount of the monomer or oligomer dropping off from the yarn by abrasion under a constant tension with a combed member is defined on the ordinate and the corresponding percent moisture content of the yarn is defined on the abscissa. In the drawing, the amount of the dropped-off monomers or oligomers is given by the ratio with respect to the weight of the yarn of the corresponding length at a processing temperature of C. As is apparent in the drawing, the amount of the oozing out of monomers or oligomers increases remarkably when the value of the moisture content exceeds 3 percent while it decreases down to one-tenth of the so-called saturated moisture content (4.5 percent) of the yarn when the moisture content of the yarn goes below 2.5 percent, more particularly below 2.2 percent. in the drawing, the curve designated with a corresponds to a yarn containing 2.5 percent by weight of water-soluble component such as monomers or oligomers, b to 2.0 percent and c to 1.6 percent, respectively.

One typical embodiment of the method of the present invention comprises bestowing a moisture content from 4 to 6 percent to an undrawn nylon filament yarn, heating the yarn after or simultaneously with the drawing operation so as to make the moisture content of the yarn lower than 2.5 percent, or more favorably lower than 2.2 percent, promptly taking up the yarn onto a package while keeping the yarn at the lowered moisture content and sealing the package thereof in a bag made of a material with very low permeability. In carrying out the aforementioned operations, caution must be taken to the control of the relative temperature and humidity of the package, taking-up speed of the yarn on the package, winding condition of the package and the length of time between taking up onto a package and scaling in the bag so as to keep the average moisture content of the yarn below 2.5 percent at the stage of sealing operation.

Another preferable embodiment of the method of the present invention comprises placing a package of the yarn within an air conditioned (for example maintained at a relative humidity of 75 percent and a temperature of 25 C.) cabinet made of a heat insulating material and provided with only a small slit for inserting the yarn and discharging it from the cabinet and delivering to the drawing stage. The processing conditions of the yarn during the drawing operation are determined in accordance with the processing conditions of the related manufacturing stages. After being delivered from the cabinet, the yarn is subjected to a drawing operation. In this connection, the takeup roller of the drawing stage is suitably heated and the yarn is wound around the roller several times so as to evaporate excess moisture contained in the yarn. Then the yarn is taken up onto a package and, instantly thereafter, is sealed in a bag made up of a low moisture permeable material.

The method of the present invention should be appreciated more when applied to the direct spinning and drawing process. In case of the process of this type, relatively easy and quick moisture absorption of the yarn manufactured causes frequent yarn breakage during the warping operation in the following weaving or knitting preparation process. By employing the method of the present invention in the direct spinning and drawing process, it is possible to decrease remarkably the number of yarn breakage during the warping stage.

One typical embodiment of the application of the method of the present invention in the direct spinning and drawing process comprises oiling suitably an undrawn filament yarn, drawing the oiled yarn by passing through drawing rollers which are heated so as to evaporate excess moisture contained in the yarn, taking up the drawn yarn onto a package and sealing the package instantly in a bag made of a low moisture permeable material. In this operation, the relative humidity of the taking-up stage should preferably be maintained below 40 percent and the moisture content of the yarn just before sealing should be kept below 2.5 percent.

As the low moisture permeable material used for sealing the package, a relatively thin film made from a thermoplastic synthetic polymer such as polypropylene, polyethylene, polyvinyl chloride or polyester should preferably be used.

The following examples are illustrative of the present invention, but are not to be construed as limiting the same.

EXAMPLE 1 An undrawn nylon-6 multifilament yarn having total fineness of 135 denier and composed of 13 monofilaments was drawn at a drawing ratio of 3.5 and the drawn multifilament yarn of 40 denier thus obtained was taken up onto a package at a takeup speed of 600 meters/min. The content of the water-soluble component within the yarn on the package was 1.6 percent. In order to process the yarn through the aforementioned sequence of operations, the following five samples were employed.

A. The package of the undrawn filament yarn was placed in the drawing chamber in the usual exposed condition and the yarn was subjected to an ordinary drawing operation. The atmosphere within the drawing chamber was maintained at 25 C. and 65 percent RH.

B. The package of the drawn filament yarn prepared in the method ofcase A was sealed with a polypropylene film bag.

C. In the method of case A, the yarn was wound around a heated drawing roller five times and the package acquired was sealed in the manner of case B. The temperature of the heated drawing roller was maintained at 150 C. and the length of the total contacting time of the passing yarn with the roller was 0.1 seconds.

D. The package of the undrawn filament yarn was placed in an air conditioned cabinet wherein the temperature was maintained at 25 C. and the relative humidity was 65 percent. The yarn was delivered from the cabinet and subjected to a drawing operation at a temperature of 30 and a relative humidity of 35 percent. After drawing, the yarn was wound five times around a roller heated at 150 C. and taken up onto a package. The package was placed in a polypropylene film bag but not sealed.

E. The package acquired in the manner of case D was sealed in a bag made ofa polypropylene film.

The aforementioned samples B to E were stored in a room maintained at a temperature of 35 C. and a relative humidity of 80 percent for three months. After this storing, all of the aforelisted samples A to E were processed to a warping on a tricot beam and the amount of monomers or oligomers which dropped off from the yarn surface and the frequency of the yarn breakage during the warping operation were recorded. Together with this test, coefficients of dynamic friction with respect to an aventurine-treated stainless steel rod were measured. As is apparent from the Table l, the sample of case E indicated good results, the same as those of case A, which was tested just after drawing operation.

TABLE 1 Samples A B C D E Moisture content just after taking up onto a package, in percent 4. 7 4. 7 '2. J 2. 0 2. 0 Moisture content after storage, in percent 4. 7 2.1! 2. 7 2. 0 Degree of dropping ofi oi monomers or ollgomers (l 0) Frequency of yarn breakage within a yarn length of 10 meters 23. 5 8. 6. 6) 1. 8

Coefficient of dynamic friction 0. 22 O. 34 0. 28 0.28 0. 21

l Little. 2 Considerable. 3 Moderate. 4 Represents the results measured on only the surface layers of the package.

EXAMPLE 2 Nylon-6 filament was spun, oiled, directly drawn, taken up onto a package and sealed under the processing conditions described below.

Bestowed moisture content 4.0%

Drawing ratio 3.5 Temperature of the drawing roller 160 C. Length of the contacting time of the yarn with the roller 0.l5 sec. Takeup speed 3.000 mJmin. Acquired multifilament 40 dcniers and yarn l3 filaments F. Taken up onto a package at a temperature of 25 C. and a relative humidity of 60 percent. Two hours after taking up, the package was sealed in a polypropylene film bag. G. Taken up onto a package at a temperature of 30 C. and a relative humidity of 35 percent. Soon after taking up, the package was placed in a polypropylene film bag. H. Taken up onto a package at a temperature of 30 C. and a relative humidity of 35 percent. Instantly after taking up, the package was sealed in a polypropylene film bag.

The above-listed three samples were stored for 3 months in a room whose temperature was maintained between 5 and 20 C. and relative humidity was maintained between 40 and percent. After this storage, the samples were processed through a warping operation together with a nonstored sample yarn and tests the same as those in Example 1 were carried out on these samples. As is apparent from the results shown in Table 2, the sample of case H presented the most favorable results together with the nonstored sample yarn.

7 il ittle Moderate.

While the invention has been described in conjunction with certain embodiments thereof, it is to be understood that various modifications and changes may be made without departing from the spirit and scope of the invention.

What is claimed is:

l. A method for manufacturing an improved polycaproamide filament yarn wherein said yarn is subjected to a drawing operation comprising heating said yarn during the drawing operation by winding said yarn around a heated roller at least five times so that the yarn has a moisture content below 2.5 percent at the end of the drawing operation and sealing a package of said yarn while retaining the moisture content of said yarn below 2.5 percent in a bag made of a low moisture permeable material instantly after said drawing operation. 

